11728337781 has 4 divisors (see below), whose sum is σ = 15637783712. Its totient is φ = 7818891852.

The previous prime is 11728337741. The next prime is 11728337801. The reversal of 11728337781 is 18773382711.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 11728337781 - 2⁶ = 11728337717 is a prime.

It is a super-2 number, since 2×11728337781² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 11728337781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11728337741) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1954722961 + ... + 1954722966.

It is an arithmetic number, because the mean of its divisors is an integer number (3909445928).

Almost surely, 2^11728337781 is an apocalyptic number.

It is an amenable number.

11728337781 is a deficient number, since it is larger than the sum of its proper divisors (3909445931).

11728337781 is an equidigital number, since it uses as much as digits as its factorization.

11728337781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3909445930.

The product of its digits is 395136, while the sum is 48.

The spelling of 11728337781 in words is "eleven billion, seven hundred twenty-eight million, three hundred thirty-seven thousand, seven hundred eighty-one".